Tube bending device



G. P. GOODE TUBE BENDING DEVICE Dec. 2, 1941.

Filed Sept. 15, 1938 INVENTORS. GODF/QEV Pmex @0005;

ATTORNEYS.

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Patented Dec. 2, 1941 UNITED STATES. PATENT OFFICE TU E ammo mavicr. Godfrey-Park Geode, Covlngton, Ky., assignor to The Lackner Compan a corporation of Ohio y, Ina, Cincinnati, Ohio,

Application September 15, 1938, Serial No. 230,080

4 Claims.

This invention relates to devices for bending tubes and more particularly to the bending of glass tubes such as are used, for example, in connection with neon signs. It is well known that tubes going to make up neon signs must be bent at various angles and it is desirable to have a device whereby this bending can be accomplished speedily and accurately as regards the degree of bend and without collapsing the tube at the point of bend.

The objects of my invention, therefore, include the provision of a device for bending glass tubes and the like by means of which such tubes may quickly be bent and whereby the angle of bend operate.

These and other objects of my invention which will be pointed out hereinafter or which will be apparent to one skilled in the art upon reading these specifications, I accomplish by that certain construction and arrangement of parts of which I shall now describe an exemplary embodiment.

Reference is made to the drawing forming a part hereof and in which:

Figure 1 is a front elevation of a device according to my invention.

Fig. 2 is a horizontal cross sectional view taken on the line 22 of Fig. 1.

Fig. 3 is a partial side elevation thereof as seen from the right of Fig. 1.

Fig. 4 is a detailed rear elevation showing the dial.

Fig 5 is a detailed perspective view of one of the tube clamps.

Fig. 6 is a detailed perspective view of the burner arrangement.

' which may, if desired, be braced as indicated at H, and which carry at the top a plate [2. Ex tending below the plate l2 and preferably integral therewith are the bending brackets l3 in which is journaled a shaft 14. This shaft, as best seen in Fig. 3, carries at its rear end a disc l5 which may, if desired, be mounted by means of a set screw passing through its hub as generally indicated at [6. The purpose of this disc will be described in more detail hereinafter. At the front there is mounted upon the shaft If a disc II. This disc may, if desired, be mounted in the same manner as the disc [5. Screwed to the disc I! is a downwardly depending strap of L-shape I8, to which is screwed another L-shaped member' indicated generally at IS. The fastening means are, of course, located at the points indicated at 20. The member I9 is slotted throughout its length to accept a square headed bolt or the like, for purposes which will later be described. It should be understood that a single member could be substituted for the members l8 and I9, if desired.

Bolted to the plate l2 as indicated at 2|, is a bracket'22 which carries the slotted extension 23. It should be understood that the members 22 and 23 could be made integral or form a single piece if desired. V

The assembly indicated at 22 and 23 comprises the fixed limb, while the assembly indicated at I8 and I9 comprises the movable limb and clamps are provided on the respective limbs to engage a tube which is to be bent. These clamps are indicated in Figs. 1 and 3 generally at 24 and areshown in detail in Fig. 5. As will be seen from Fig. 5, these clamps include a base 25 upon which are mounted two generally L-shaped members 21 which are vertically interspaced. An opposing clamping bar 28 is pivoted on the rod 29 which extends between the member 21, and the member 28 is urged. into clamping position by means of the torsion spring indicated at 30. A rod 3| may, if desired, be provided as a handle for the clamping bar 28. member 26 is provided with an elongated slot 32 for attachment of the clamp 24 into the member 23 or 19 as the case may be. horizontally disposed slot 32 it is possible to adjust the lateral position of the. clamp for a purpose which will be described hereinafter.

The lower limb lS carries an L-shaped extension 33 which is fastened by means of the nut and bolt indicated at 34. This member serves as an end gauge so that if a number of tubes are to be bent at a certain distance from their ends, the device may be set up and for successive bending operations it is only necessary to see that the tube abuts against the horziontal portion 33a of the member 33.

From the foregoing it will be clear that a tube I to be bent is inserted intothe device with itslower end abutting the portion 33a and clamped in the two clamps 24. After the area of the bend has been adequately heated itis only necessary to swing the lower limb of the device as indicated by the arrow A in Fig. 1. Referring again to the disc 15 which is shown in more detail in Fig. 4, it will be noted that this disc is provided with a notch I51: and a series of graduations I5b. Mounted on a bracket Ilia is a spring member lilb having a projection I Be. It will be clear that as the lower limb is rocked in the direction indicated by the arrow A in Fig. 1 (clockwise), the disc l5 as viewed in Fig. 4 will turn in a counterclock- It should be noted that the base By virtue of the- In order to soften the glass prior to bending, I

provide a burner arrangement which will now be described by reference to'Eigs. 1 and 6. I prefer to use as 'a fuel a mixture of air and gas, and I therefore provide air and gas lines as indicated in Fig. 1 and provide them with appropriate valves 35 and 30. A T fitting at 31 serves to bring the gas and air lines together and the mixture passes through a flexible conduit 38 and additional piping generally indicated at 39 to the burners. The burners themselves have been deleted from Figs. 1 and 2m the interest of clarity and the burner arrangement is shown in detail in Fig. 6. It will there be seen that the burner arrangement consists of three burner nozzles 40 arranged to surround the tube to be bent. The tube itself is indicated at II. A simple construction may be made using simple pipe fittings and elbows by means of which the three burners may be caused to operate in a single plane. As shown in Fig. 6, in sequence, the first burner is connected by means of a T fitting lilo and the second burner bymeans of an elbow 40b, and a T fitting "c. The combination of three elbows indicated respectively at Id, We and 40 serves to bring the third burner 40 back to the same plane as the other two. A swivel fitting of any conventional type is provided at 42 so that the entire 'burner unit may be swung aside while tubing is being inserted or removed from the bending device.

Care must be taken in the bending of glass tubing that the tubing be not collapsed particularly in applications connected with neon signs. In order to avoid any such difficulty I provide two expedients. The one involves the lateral displaceability of the clamping members 24 by means of the horizontal slot construction 32. I have found that the center. of the bend should be located on a line bisectingthe angle of the bend and h -way between the inner and outer radius of t e bend. This fact is illustrated in Figs. '7 and 8 where it will be seen that for a 90 degree bend the center of bend will be displaced from the axis of the tube by the distance :2: and in the case of 135 degree bend by the distance y. The distances :1: and y and the like can readily be determined graphically and the clamps 24 can be appropriately adjusted.

A further expedient involves the maintaining of pressure within the tube during the bending process. For this purpose I provide a T in the air line as indicated at 43, to which is connected an air line 44. The air line terminates in another T fitting 45, the end of which is left open. A pipe 46 branching from the T is connected through a flexible hose 4! to the upper end ofthe tube to be bent, as indicated at 48. A cork shown at 49 in Fig. 3 is inserted into the bottom of the tube. From this description it will be seen that air is constantly flowing through the pipe 44 and out through the open end of the T 45. When the tube is ready for bending the operator may place his finger over the open end of the tube 45 whereby the air pressure will be transmitted through the tuning 46 and 41 to the tube Ii which is being bent. As soon as'the bending operation is completed the cork llmay be removed so that air will fiow through the bent tube to cool the same. When the tube has been adequately cooled, the operator may remove his finger from the T 45, and disconnect and unclam the tube.

It will be understood that various modifications may be made in my invention without de- 1. In a device for bending tubes, a fixed arm and a pivoted. arm normally disposed in align- 'ment, and tube clamps mounted respectively on said arms, said clamps being adjustable laterally in relation to said arms, whereby the position in which a tube is clamped with respect to the pivot point of said pivotedarm may be varied.

2. In a device for bending tubes, 9. frame, a shaft rotatably mounted in said frame, an arm fixedly mounted on said frame and an arm fixedly mounted perpendicular to said shaft on one end thereof, said arms being normally in alignment, tube clamping means on said arms substantially at the adjacent ends thereof, a disc having a notch, settably fixed on said shaft, and a member mounted on said frame resiliently engaging said disc and having a portion adapted to enter said notch, whereby to limit the rotation of said shaft upon engagement thereof with said notch.

3. In a device for bending tubes, 8. frame, a-

ment, tube clamping means on said arms sub stantially at the adjacent ends thereof, a disc having a notch, settably fixed on said shaft, and a member mounted on said frame resiliently engaging said disc and having a portion adapted to enter said notch, whereby to limit the rotation of said shaft upon engagement thereof with said notch, said disc carrying indicia. to indicate the degree of bend whereby upon setting of said disc to a desired angle a tube to be bent, will be bent to said angle.

4. A device for bending tubes comprising a frame, a shaft rotatably mounted in said frame, an arm fixedly mounted on said frame and an arm fixedly mounted perpendicular to said shaft on one end thereof, said arms being normally in alignment, tube clamping means on said arms substantially at the adjacent ends thereof,'means for gauging and limiting the rotationof said shaft, a burner assembly comprising a plurality of nozzles arranged to be disposed substantially radially to a tube to be bent, said burner assembly being pivotally mounted whereby it may be swung bodily aside during insertion or removal of a tube, a fuel line feeding said burner assembly, an air line and a gas line connected to said fuel line, and a branch line from said air line terminating in a flexible tube,'said branch line having a by-pass opening, said flexible tubing being attachable to a tube to be bent, and means for stopping the free end of the tube to be bent, whereby upon stopping the by-pass opening pressure may be applied to the tube to be bent.

GODFREY PARK GOODE. 

